Screw-jack.



RM. PATTERSON.

SCREW JACK.

APPLICATION FILED SEPT.14,1909.

Patented Aug. H, 1914:.

i T Flio 11' NKLIN 11d. PATTEON, OF BAYONNE, NEW JERSEY.

SCREW-TACK.

Specification of Letters Patent.

Patented Aug. 1111,. 131d.

Application filed fleptember 1c, 1909. Serial No. 51.15%.

To all whom it may concern:

Be it known that I, FRANKLIN M. PATTER- soN, a citizen of the United States, and resident of the city of Bayonne, county of Union, State of New Jersey, have invented an Improvement in Screw-Jacks, of which the following is a specification.

My invention has reference to screw jacks and consists of certain improvements which are fully set forth in the following specificatio.. and are shown in the accompanying drawings which form a part thereof.

The object of my invention is to provide a compact construction of operating mechanism in a screw jack which will be powert'ul in operation, simple in construction, durable in action and easily repaired.

My invention consists of certain features of construction which are fully described hereinafter and more particularly defined in the claim.

The features of construction will be better understood by reference to the drawings, in which:

Figure 1 is a sectional elevation of a screw jack embodying my improvements; Fig. 2 is a sectional plan view of the same taken on line a:--w of Fig. 1; Fig. 3 is a front elevation of the lever mechanism for operatin the jack.

2 is t e body of the jack and is made hollow; and closed at the bottom where it is connected to a base plate 3 by screws 4:, the center portion of which base plate comprises a solid central boss 5 which is formed with the upwardly extending tubular bearing 6. The upper part of the body 2 is provided with a double polygonal bearing 7 having an interposed space 8 and in which bearing is guided a vertical tubular lifting plunger 9 having a polygonal outer surface adapted to fit the bearin 7. This plunger is provided with an en arged head as at 10. This plunger is made tubular, as at 11, and 1ts lower part is'provided with a vertical screwthread 12, the internal diameter ()fWlllCll is less than the tubular chamber 11.

13 is a vertical screw which engages the screw-threaded lower part 12 of the lifting longer and extends upwardly into the tuhula!- chamber 11. The lower part of this screw 13 is provided with a bevel gear '14:

and below the bevel gear there is a journaled bearing 15 which extends down into the tubular bearing 6 in the base plate.

16 is a hard steelstep in the bottom of the tubular bearing 6; it is preferably curved on the top and receives the downward thrust of the ournal of the screw part 13. The upper part of this screw 13 is rovided with an internal screw-threaded ho e 17 in which a screw 18 extends, said screw 18 having a head 19 of greater diameter than the outside diameter of the screw 13 so as to form an annular shoulder 20 about the screw which will act as a limit sto for the upward movement of the tubu ar plunger 9 during its travel upwardly upon the screw 13 by the rotation thereof, the shoulder 21 at the bottom of the chamber part 11 strik ing the annular shoulder 20 of the screw head 19 and thereby preventing any further movement of the plun er with respect to the screw and which might otherwise cause disengagement of it unintentionally.

22 is a plug which is screwed into the upper end of the tubular part 11 so as to form an upper bearing surface with the flanged head 10, and at the same time to protect the screw and chamber 11 and keep dirt out of the same. When the plunger is moving down, its downward motion is limited by the plug 22 coming in contact with the top of the head 19 of the screw 18 carried by the lifting screw 13. As shown in Fig. 1, this plunger is not quite down to its lowest level, but almost so.

23 is a transverse operating shaft and is carried in bearing 24 projecting from the body 2 of the jack; and this shaft is provided on the end with a bevel pinion 25 which meshes with the bevel gear 14 of the screw 13. Both of these bevel gears are housed within the body 2. The end of the shaft 23 extends beyond the bearing 24 to a small extent and is then reduced in diameter as at 26 but between the part 26 and the cylindrical part 23 there is a square part 27 which has a width exactly equal to the width of the ratchet wheel 28. This ratchet -wheel is provided with a square hole and fits over the square part 27 of the shaft 23.

29 is a ratchet lever head having a transverse slot in which the ratchet wheel 28 and the ratchet pawl 30 are placed and is also provided at the top with a socket 31 in which the lever or handle 32 may be detachably inserted while operating the jack. One of the walls of the head 29 is provided with a large hole 33 which fits over the end of the shaft 23 and the other wall of the head has a smaller circular hole 34 which fits over the small diameter 26 of the shaft. As will be understood the head, with the'ratchet wheel within it is placed over the end of the shaft in the position shown in Fig. 1, in which case the head will have a bearing at 33 and 34 and may be freely rocked. The ratchet wheel 28 will be secured to the square part 27 of the shaft so that when it is rotated the shaft 23 will rotate with it. A washer 35 and a cotter pin 36 holds the head 29 with its ratchet wheel in position on the shaft. The pawl 30 is pivoted at 37 in the head 29 and a spring 38 is placed between the pawl and the bottom of the head and will cause the pawl to operate either at-the right or left end. In Fig. 3 the pawl is indicated in its intermediate position. It is pushed into one position to cause the plunger to be moved upward by the oscillation of the head 29 and in the-other position to cause the plunger to be lowered by the same oscillatory movement of the head 29. Any other suitable ratchet or other mechanism may be employed for imparting a rotary oscillation to the shaft 23.

4 In dismantling the machine it is only necessary to remove the plug 22, the screw 18 and the base plate 8, when the screw 13 may be readily unscrewed from the plunger and the latter lifted out at the top. By removing the cotter pin 36 the head 29 may be removed and then the shaft 23 withdrawn through the body 2. In the reverse way, the parts may be assembled and the work of assembling is reduced to a minimum because of the few number of parts and particularly because of the simple way in which these cooperate. It will be further llIldQlStOOd that to lubricate the screw 13 and the gearing it is only necessary to insert the lubrieating material in the tubular chamber 11 below the plug 22. This lubricating material may be tallow or other self supporting grease composition which, under excessive friction, will heat and work downward. If desired any other lubricant may be used, as found desired.

The construction here shown is very strong and not liable to become broken under the most rough usage. It cannot be oper ated beyond the proper limits and to thereby disengage any of the parts, nor to cause 1 any of the parts to jam. The machine work upon the structure is reduced to a minimum .few as can be employed. The thrust is in a downward direction through the central boss 5 of the base so that the smallest strain possible is put upon the body and consequently the latter may be made reasonably light so as to reduce the weight of the lack as greatly as possible;

I have shown my inventionin the form which I have found excellently adapted for the purpose for which itis intended; and while I prefer the construction shown, I do not limit myself to the details thereof, as these may be modified without departing from the spirit of the invention.

Having now described my invention what I claim as new and desire to secure by Letters Patent, is:

In a screw jack, the combination of a body having a polygonal-shaped guide at the top, a tubular plunger outwardly flanged at its top and having its outer part polygonalshaped in cross section to fit the guide of the body and further having its interior formed with a tubular part of large diameter opening through the top and terminating at. the bottom in a shoulder and with a tubular part'of relatively small diameter below the shoulder provided with screw threads, a vertical screw engaging the screw threads at the lower end of the plunger and journaled at the bottom in the body of the jack, a flange detachably secured to the top of the screw and overhanging it to engage the shoulder of the plunger when it rises to limit its upward movement, a removable plug secured in the upper end of the plunger and adapted to come into contact with the flanged partv on the top of the screw to limit the downward movement of the plunger before the flange portion thereof reaches the top of the body part, and by the removal of which plug access may be had for removing the detachable flange from the top of the screw when necessary to remove the plunger, and means for rotating the screw and holding it against longitudinal movement in the body.

In testimony of which invention, I hereunto set my hand.

FRANKLIN M. PATTERSON.

Witnesses:

PATRICK J. WALSH, CHAS. STELL. 

